Implement commit for unaccelerated canvas with GPU compositing

third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp

Index: third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp b/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp
index 72e85946ba18f2ac8005b4e9bf4416328c9de968..de359faca13ed094734a9d7ea84a2ee8b2a3081b 100644
--- a/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp
+++ b/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp
@@ -11,16 +11,22 @@
 #include "cc/quads/solid_color_draw_quad.h"
 #include "cc/quads/texture_draw_quad.h"
 #include "cc/resources/returned_resource.h"
+#include "gpu/command_buffer/client/gles2_interface.h"
+#include "platform/RuntimeEnabledFeatures.h"
+#include "platform/graphics/gpu/SharedGpuContext.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "public/platform/InterfaceProvider.h"
 #include "public/platform/Platform.h"
 #include "public/platform/modules/offscreencanvas/offscreen_canvas_surface.mojom-blink.h"
 #include "third_party/khronos/GLES2/gl2.h"
+#include "third_party/khronos/GLES2/gl2ext.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/core/SkImage.h"
 #include "third_party/skia/include/core/SkXfermode.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/transform.h"
+#include "wtf/typed_arrays/ArrayBuffer.h"
+#include "wtf/typed_arrays/Uint8Array.h"
 
 namespace blink {
 
@@ -46,6 +52,102 @@ OffscreenCanvasFrameDispatcherImpl::OffscreenCanvasFrameDispatcherImpl(
                                       mojo::GetProxy(&m_sink));
 }
 
+// Case 1: both canvas and compositor are not gpu accelerated.
+void OffscreenCanvasFrameDispatcherImpl::setTransferableResourceCase1(
+    cc::TransferableResource& resource,
+    RefPtr<StaticBitmapImage> image) {
+  std::unique_ptr<cc::SharedBitmap> bitmap =
+      Platform::current()->allocateSharedBitmap(IntSize(m_width, m_height));
+  if (!bitmap)
+    return;
+  unsigned char* pixels = bitmap->pixels();
+  DCHECK(pixels);
+  SkImageInfo imageInfo = SkImageInfo::Make(
+      m_width, m_height, kN32_SkColorType,
+      image->isPremultiplied() ? kPremul_SkAlphaType : kUnpremul_SkAlphaType);
+  // TODO(xlai): Optimize to avoid copying pixels. See crbug.com/651456.
+  image->imageForCurrentFrame()->readPixels(imageInfo, pixels,
+                                            imageInfo.minRowBytes(), 0, 0);
+  resource.mailbox_holder.mailbox = bitmap->id();
+  resource.mailbox_holder.texture_target = 0;
+  resource.is_software = true;
+
+  // Hold ref to |bitmap|, to keep it alive until the browser ReturnResources.
+  // It guarantees that the shared bitmap is not re-used or deleted.
+  m_sharedBitmaps.add(m_nextResourceId, std::move(bitmap));
+}
+
+// Case 2: canvas is not gpu-accelerated, but compositor is
+void OffscreenCanvasFrameDispatcherImpl::setTransferableResourceCase2(
+    cc::TransferableResource& resource,
+    RefPtr<StaticBitmapImage> image) {
+  // TODO(xidachen): When committing the first frame, there is no instance of SharedGpuContext
+  // yet, calling SharedGpuContext::gl() will trigger a creation of an instace, which requires
+  // to create a WebGraphicsContext3DProvider. This process is quite expensive, because
+  // WebGraphicsContext3DProvider can only be constructed on the main thread, and bind to the
+  // worker thread if commit() is called on worker. In the subsequent frame, we should already
+  // have a SharedGpuContext, then getting the gl interface should not be expensive.
+  // Try to optimize the first frame in the future.

[Justin Novosad, 2016/10/04 14:20:48]

You need a crbug for this. There is a potential for an unexpected deadlock here.
 For example, If the main thread is waiting on a spinlock (possibly implemented
on top a SharedArrayBuffer) that is to be unlocked by a worker after commit(),
the browser should not hang.

[xidachen, 2016/10/04 14:43:06]

Done.

+  gpu::gles2::GLES2Interface* gl = SharedGpuContext::gl();
+
+  SkImageInfo info = SkImageInfo::Make(
+      m_width, m_height, kN32_SkColorType,
+      image->isPremultiplied() ? kPremul_SkAlphaType : kUnpremul_SkAlphaType);
+  RefPtr<ArrayBuffer> dstBuffer =
+      ArrayBuffer::createOrNull(m_width * m_height, info.bytesPerPixel());
+  // If it fails to create a buffer for copying the pixel data, then exit early.
+  if (!dstBuffer)
+    return;
+  RefPtr<Uint8Array> dstPixels =
+      Uint8Array::create(dstBuffer, 0, dstBuffer->byteLength());
+  image->imageForCurrentFrame()->readPixels(info, dstPixels->data(),
+                                            info.minRowBytes(), 0, 0);
+
+  GLuint textureId = 0u;
+  gl->GenTextures(1, &textureId);
+  gl->BindTexture(GL_TEXTURE_2D, textureId);
+  GLenum format =
+      (kN32_SkColorType == kRGBA_8888_SkColorType) ? GL_RGBA : GL_BGRA_EXT;
+  gl->TexImage2D(GL_TEXTURE_2D, 0, format, m_width, m_height, 0, format,
+                 GL_UNSIGNED_BYTE, 0);
+  gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+  // The pixel data will be uploaded to GPU memory, we have to keep the GPU
+  // memory alive until browser ReturnResources, so here we put textureId for
+  // that piece of GPU memory into a hashmap.
+  m_cachedTextureIds.add(m_nextResourceId, textureId);
+  gl->TexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, m_width, m_height, format,
+                    GL_UNSIGNED_BYTE, dstPixels->data());
+
+  gpu::Mailbox mailbox;
+  gl->GenMailboxCHROMIUM(mailbox.name);
+  gl->ProduceTextureCHROMIUM(GL_TEXTURE_2D, mailbox.name);
+
+  const GLuint64 fenceSync = gl->InsertFenceSyncCHROMIUM();
+  gl->ShallowFlushCHROMIUM();
+  gpu::SyncToken syncToken;
+  gl->GenSyncTokenCHROMIUM(fenceSync, syncToken.GetData());
+
+  resource.mailbox_holder =
+      gpu::MailboxHolder(mailbox, syncToken, GL_TEXTURE_2D);
+  resource.read_lock_fences_enabled = false;
+  resource.is_software = false;
+}
+
+// Case 3: both canvas and compositor are gpu accelerated.
+void OffscreenCanvasFrameDispatcherImpl::setTransferableResourceCase3(
+    cc::TransferableResource& resource,
+    RefPtr<StaticBitmapImage> image) {
+  image->ensureMailbox();
+  resource.mailbox_holder = gpu::MailboxHolder(
+      image->getMailbox(), image->getSyncToken(), GL_TEXTURE_2D);
+  resource.read_lock_fences_enabled = false;
+  resource.is_software = false;
+
+  // Hold ref to |image|, to keep it alive until the browser ReturnResources.
+  // It guarantees that the resource is not re-used or deleted.
+  m_cachedImages.add(m_nextResourceId, std::move(image));
+}
+
 void OffscreenCanvasFrameDispatcherImpl::dispatchFrame(
     RefPtr<StaticBitmapImage> image) {
   if (!image)
@@ -71,39 +173,19 @@ void OffscreenCanvasFrameDispatcherImpl::dispatchFrame(
   // TODO(crbug.com/645590): filter should respect the image-rendering CSS property of associated canvas element.
   resource.filter = GL_LINEAR;
   resource.size = gfx::Size(m_width, m_height);
-  if (image->isTextureBacked()) {
-    image->ensureMailbox();
-    resource.mailbox_holder = gpu::MailboxHolder(
-        image->getMailbox(), image->getSyncToken(), GL_TEXTURE_2D);
-    resource.read_lock_fences_enabled = false;
-    resource.is_software = false;
-
-    // Hold ref to |image|, to keep it alive until the browser ReturnResources.
-    // It guarantees that the resource is not re-used or deleted.
-    m_cachedImages.add(getNextResourceIdAndIncrement(), std::move(image));
-  } else {
-    std::unique_ptr<cc::SharedBitmap> bitmap =
-        Platform::current()->allocateSharedBitmap(IntSize(m_width, m_height));
-    if (!bitmap)
-      return;
-    unsigned char* pixels = bitmap->pixels();
-    DCHECK(pixels);
-    SkImageInfo imageInfo = SkImageInfo::Make(
-        m_width, m_height, kN32_SkColorType,
-        image->isPremultiplied() ? kPremul_SkAlphaType : kUnpremul_SkAlphaType);
-    // TODO(xlai): Optimize to avoid copying pixels. See crbug.com/651456.
-    image->imageForCurrentFrame()->readPixels(imageInfo, pixels,
-                                              imageInfo.minRowBytes(), 0, 0);
-    resource.mailbox_holder.mailbox = bitmap->id();
-    resource.is_software = true;
-
-    // Hold ref to |bitmap|, to keep it alive until the browser ReturnResources.
-    // It guarantees that the shared bitmap is not re-used or deleted.
-    m_sharedBitmaps.add(getNextResourceIdAndIncrement(), std::move(bitmap));
-  }
   // TODO(crbug.com/646022): making this overlay-able.
   resource.is_overlay_candidate = false;
 
+  if (!image->isTextureBacked() &&
+      !RuntimeEnabledFeatures::gpuCompositingEnabled())
+    setTransferableResourceCase1(resource, image);
+  else if (!image->isTextureBacked() &&
+           RuntimeEnabledFeatures::gpuCompositingEnabled())
+    setTransferableResourceCase2(resource, image);
+  else
+    setTransferableResourceCase3(resource, image);
+
+  m_nextResourceId++;
   frame.delegated_frame_data->resource_list.push_back(std::move(resource));
 
   cc::TextureDrawQuad* quad =
@@ -134,6 +216,7 @@ void OffscreenCanvasFrameDispatcherImpl::ReturnResources(
   for (const auto& resource : resources) {
     m_cachedImages.remove(resource->id);
     m_sharedBitmaps.remove(resource->id);
+    m_cachedTextureIds.remove(resource->id);
   }
 }